A wide variety of trailers have been developed for transportation of various goods via roadways. Such trailers include platform trailers, refuse trailers, dump trailers as well as other types. Further, within these types of trailers, various configurations may be available, such as frame and frameless dump trailers, which are suitable for alternative applications. In the various trailers configurations, suspension systems are provided in association with wheels of the trailer to provide a smoother ride and facilitate handling and transportation of loads thereby. As it is desired to maximize the load carrying capacity of the trailer, the characteristics of the suspension system and mounting arrangement become an important aspect of the trailer design.
Prior trailers typically use a steel suspension system which includes the steel hangers, steel brackets, suspension arm, air spring, and shock absorbers. The suspension arm is attached to the axle and the air spring; steel hangers, and steel brackets are generally attached directly to one or more central I-beams or a sub-frame foundation over the rear wheels of the frameless trailer. For various applications, it may also be necessary to bolster the structural strength of components to handle expected loads. For example, the rear of the frameless dump trailer may require heavier duty structural components such as the steel suspension and steel subframe.
In the past, trailers had been manufactured using plates of aluminum sheet welded together and reinforced with reinforcing ribs. Now, some trailers are being manufactured using high strength extruded aluminum plate such as 6061. The extruded aluminum provides great advantages in terms of strength while eliminating much of the need for reinforcing ribs along the trailer body. However, the strength and durability required for many of the subframe and suspension components have substantially prevented the use of aluminum on a suspension subframe assembly. Accordingly, these material advantages have not been utilized in the structural components such as the steel suspension and steel subframe.
It would therefore be desirable to provide a suspension subframe assembly which has the desired strength characteristics, while being of reduced weight, and which allows for various suspension systems to be integrated into the trailer construction in a simplified manner. It would also be desirable to provide a suspension subframe assembly which has and integrated hanger for mounting of suspension system components.